1. Lesson 6-9: Variation Objective: Students will: oFind the constant of variation and setup direct and inverse variation equations oUse variation equations to solve problems

2. Direct Variation Equations: or Why direct? Take or, where k = 2 If y goes up, x must go up y and x move the same → direct “k” is the constant of variation – must stay constant

3. Inverse Variation Equations: or Inverse → opposite → if y goes up, x must go down… Choosing Identify the variables Ask: if the one value increases, what will the other do? increase also → direct decrease → inverse

4. Example 1 The force applied to a spring causes the length to increase. 8 pounds makes the spring 4 inches. Find k and write a general equation. Which type of variation? Direct What would be the x variable? y? x: pounds y: inches What would be the length if the weight is 20lbs?

5. Example 2 Time (t) required to do a job varies inversely with the number of people working. It takes 4hrs for 12 people to put up bleachers. Write the equation to represent the problem. How long would it take 3 people to do the same job.

6. Marker Board pg 283-284 2 8 10 14 15 17 31 Assignment/6-9/283-284/3-27M3,34-42e